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nahpets
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Joined: 05 Oct 2003
Posts: 1178
Location: Montreal, Canada
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 Posted: Fri May 14, 2004 3:11 am Post subject: hdparm giving slow transfer rates |
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Two of my hard drives seem to be giving me slow xfer rates as compared to rates reported by others in the forums. The first drive is a 120 GB 7200 RPM Western Digital and the second is a 40GB 7200 RPM Seagate. Does anyone know how to get faster xfer rates from the drives?
| Quote: |
# hdparm -i -tT /dev/hda /dev/hdb
/dev/hda:
Model=WDC WD800JB-00CRA1, FwRev=17.07W17, SerialNo=WD-WMA8E6274529
Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
RawCHS=16383/16/63, TrkSize=57600, SectSize=600, ECCbytes=40
BuffType=DualPortCache, BuffSize=8192kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=156301488
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=no WriteCache=enabled
Drive conforms to: device does not report version:
* signifies the current active mode
Timing buffer-cache reads: 552 MB in 2.01 seconds = 274.12 MB/sec
Timing buffered disk reads: 120 MB in 3.04 seconds = 39.53 MB/sec
/dev/hdb:
Model=ST340824A, FwRev=3.05, SerialNo=3HE05KTG
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=0
BuffType=unknown, BuffSize=2048kB, MaxMultSect=16, MultSect=16
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=78165360
IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes: pio0 pio1 pio2 pio3 pio4
DMA modes: mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=no WriteCache=enabled
Drive conforms to: device does not report version: 1 2 3 4
* signifies the current active mode
Timing buffer-cache reads: 556 MB in 2.01 seconds = 275.97 MB/sec
Timing buffered disk reads: 102 MB in 3.00 seconds = 33.98 MB/sec
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Malakin
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Joined: 14 Apr 2002
Posts: 1692
Location: Victoria BC Canada
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| Posted: Fri May 14, 2004 3:25 am Post subject: |
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Cache read performance is based on cpu and memory bandwidth. I guess you have a slower cpu/mobo then most?
Your disk read performance looks fine though. |
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nahpets
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Joined: 05 Oct 2003
Posts: 1178
Location: Montreal, Canada
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| Posted: Fri May 14, 2004 3:49 am Post subject: |
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| Have a Dell PIII 866. Shouldn't the CPU speed not really affect the read speed since DMA is being used? |
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John5788
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Joined: 06 Apr 2004
Posts: 2140
Location: 127.0.0.1
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| Posted: Fri May 14, 2004 4:19 am Post subject: |
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if you want faster speeds, u could tweak ur hdd using hdparm, but dont break it.
_________________
John5788 |
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Malakin
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Joined: 14 Apr 2002
Posts: 1692
Location: Victoria BC Canada
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| Posted: Fri May 14, 2004 5:17 am Post subject: |
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| Quote: | | Shouldn't the CPU speed not really affect the read speed since DMA is being used? |
It effects it a litte bit, if you put a cpu in there that was twice as fast you'd get a few more MB/s, so 39.5MB/s might go to 42MB/s although I'm just speculating.
Here's a bit of the man file, note that cache reads (-T) have nothing to do with the hard drive, don't know why people always post them.
| Quote: | -T Perform timings of cache reads for benchmark and comparison purposes. For meaningful
results, this operation should be repeated 2-3 times on an otherwise inactive system
(no other active processes) with at least a couple of megabytes of free memory. This
displays the speed of reading directly from the Linux buffer cache without disk
access. This measurement is essentially an indication of the throughput of the pro-
cessor, cache, and memory of the system under test. If the -t flag is also speci-
fied, then a correction factor based on the outcome of -T will be incorporated into
the result reported for the -t operation.
-t Perform timings of device reads for benchmark and comparison purposes. For meaning-
ful results, this operation should be repeated 2-3 times on an otherwise inactive
system (no other active processes) with at least a couple of megabytes of free mem-
ory. This displays the speed of reading through the buffer cache to the disk without
any prior caching of data. This measurement is an indication of how fast the drive
can sustain sequential data reads under Linux, without any filesystem overhead. To
ensure accurate measurements, the buffer cache is flushed during the processing of -t
using the BLKFLSBUF ioctl. If the -T flag is also specified, then a correction fac-
tor based on the outcome of -T will be incorporated into the result reported for the
-t operation. |
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nahpets
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Posts: 1178
Location: Montreal, Canada
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| Posted: Fri May 14, 2004 7:05 am Post subject: |
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| Hmm... so I guess your processor speed will have a bigger impact on the cache-read speed, which would explain why I was seeing people reporting speeds of 500-1000 MB/s for that particular benchmark. |
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